Process of gluing wood.



W. IVI. GROSVENOR.

PROCESS 0F GLUING WOOD.

APPLICATION FILED 1AN.16. 1918.

1,299,795. Patented Apr. 8, 1919.

glue Layers A WILLIAM M. GEosvENote, E NEW` YORK, N. Y., As'sIGNon To PERKINS GLUE COMPANY,

A coEPonA'rIoN 0E PENNSYLVANIA.

j PROCESS 0F GLUING WOOD.

' `Application filledv anuary 16,1918. Serial No. 2,212,04l5.'v

To all whom it may concern.'

Be it known that I, WILLIAM M. Gnosv vENoR, a citizen of the United States, and a vent.

resident of New York city, in the county of New York and State of :New York,'have invented certain new and useful Improvements in Processes of Gluing Wood, of which the following is aspecification.

, My invention relates to improvementsvin processes for gluing wood and is particularly applicable to the gluing up of-wood panels, veneers and joints for furniture and similar work. 'For many years animal glue was the only glue generally used for .this

purpose, but this has nw been largely supplanted by vegetableglue, made from a starchy carbohydrate base, water and a solglue, cassava starch has been generally used, and ithas generally been. found' necessary to hydrolyz'e or degenerate the starch a certain extent before dissolving'it in the water lwith the solvent, 'and' in spite of such deinto'the wood, due to its fluidity, that insuiicient is left on the surface to make a de-f sirable joint and, furthermore, the large yamount of waterso wets the wood that av much longer time is required for drying out, al disadvantage quite seriousin niost commercial practlee. `If such fluid-vegel table glue-be applied to wood veneers, and

especially thin veneers, much the same difculties are encountered, even vif the glue be just as viscou'sas regular ,vegetablgJ glue,

but contains an excessive amount of water. The object of my invention is to' provide a 'process whereby lthese diiliculties, A attend-f Specification of Letters Patent.

In the making of such vegetable form a /strong oint. l

Patenten Apr.

wise, or both, thereby preventing a desirable joint from being obtained. According to my invention, after the glue is applied, Il allow itto stand without anyv pressure, oronly slight pressure being applied for a time sulicient to permit a substantial amount of the water to' dry vout of the glue, before subjecting the glue of the joint to thevrelatively heavy pressure, By allowing the glue to V.stand before Acom letingthe pressure of the glue into the .wood pores, theglue losesl some of water to the wood or to the air', or v both, and thickens somewhat, after which the relatively heavy pressure no longer causes excessive penetration Y or materiall squeezing outat the edges. I find that the water absorbed by the wood before the glue is pressed I vmaterially into the wood is more quickly, dried outjthan is the water in the glue pressed into the wood. I find that the depth of penetration of the glue into the wood pores depends upon the fluidity of the minute j portions of the glue which-'have already penetrated, and the pressure applied, and that. the less the glue is forced 4into the wood, the quicker the wood will dry out, and that the 'less the glue is forced -out sidewise, together-.with the less it is forced intothe wood, themore glue is left' between the wood surfaces to form thejoint, although nally there must be suflicient penetration into the wood for the glue to takev a irnrhold thereon to form a'secure joint@` l Thus during the first stagethere is no ina-1f terial penetration of the glue into the wood and then when thel relatively ,heavy pressure is applied the glue is only forced into the superficial pores ofthe wood sufficient to secure a good hold thereon, so that ample glue is left between,4 the wood surfaces-to The examples glven below taken in connection with thel accompanying 'sheet of ant on* the use 'off relatively fluid glues or of a press containing a stack of veneers withv f glues containing eti-relatively4 large amount of water may be substantially overcome.

I nd-that when such dilutev glues are applied and then promptly subjected to high pressure, as is done 1n" commercial practice,,the glue is forced deep into the pores ofthe wood, or much of'it forced out side- 4part of the 'water has dried out ofthe glue 110 v into the wood, or rbefore 'completing the thereon. l This illustrates the first step of the process.A In Fig. 2 the second step is illustrated, in which the press is operated to apply pressurevto further force the glue Aintothe pores of the wood and the glue allowed to substantially dry out under pressure.

In the lrawings cor-e pieces are indicated at 1, 2, 3 and 4'with a layer of glue on each' vside thereof. f Veneers 5 and 6 with a coatling of glue applied thereto on the sides adjacent the lcore l, are vplaced adjacent the l core 1, as shown in Fig. 1. Veneers 7 and 8,

. 9 and 10, and 11 and 12 with similar glue and the whole arranged to form a stack in the press, P.

coated surfaces are vplaced against the cores 2,13 and 4 inA thp vsame manner, respectively,

After thevnecessaryamount of water has driedout of the. glue, pressure is applied' to the stack as indicated in Fig. 2 and the glue forced into the superficial pores of the Example 1: 100.pounds of corn starch are and during 'constant agitation thereof 8 `.pounds ofcaustic soda dissolved in 32 'pounds of W -30 -minutes .being taken, for-.the addition.

ater are slowly added, about 20 The ,addition of the caustic soda causes the starch to be dissolved into a homogeneous colloidal glue. .The stirring is preferably continuedv untll the batch is used up, as standing tends tocause it to gelatinize. While this glue will flow readily through two inch pipes,

the pipes should be cleaned .of glue before' being allowed to stand, idle for any prolonged, period, as for a1 day or more. VThe glue is preferably-applied toboth woodv surf` faces to be joined,.but good lresults can 'be obtained by application to, one surface only,-

' and-it gives better -resultsif at'leastone of l the wood .members is greater than large amount Jg inch --In .order' that the relatively of water .inthe glue (32 to 4 vin thickness.

parts by weight,` p er part of dry starch base) a may not prove disadvantageous, the glued tial pressure being applied, so that a sub- ,stantialpart ofthe water'will/dry out vof wood surfaces,v after being placedinjuxtaposition to one another, are allowedtostand for 'about 3% hour, with the pressureV of. their own weight merely,or without any substanthe glue'before the glue is materially pressed' i' pressure of the glue into the '.wood.; Then! a relatively heavy pressure, of 100 pounds vper square'inchmaybe appliedV to complete the pressure of the glue into the wood and the glue allowed to v-furtherdry out and set L under 'such pressure.

' f In selecting the corn starch base,.a starch havlng a viscosity of from 20 1:0526 at 20. to v1 by Perkins viscosimeter', .is preferred.-

4soldered into the end having a round. center quickly at its floating level in water at F.

The Perkinsviscosimeter may beconstiucted of brass tubing 1.295vinches outside diameter, 0.012 inch thick,1and 3 inches long, and having a flat brass bottom 0.080 inch thick hole 0.070 inch in diameter, the total weight being 39.63 grams, and all edges being made smooth-removing practically no weight, the i hole 'being polished until thev cup placedl floats upright and. -fills up tov the point of sudden sinking by top overflowin 16 ,seconds. i

In making the viscosity test above de? scribed, about 350 grams of starch may -be mixed'with 20 times .its weight 4of' water and boiled' Afor 10 minutes with dry live steam at 100 pounds pressure and tested for viscosity while .at about 195 F. by placing the Perkins cup viscosimeterl therein and measuring the number of seconds for it .to

sink by top overflow. When I speak of the` y viscosity being 20 lto 26 at 20 to 4l, I meanI thatvit takes from 20 to 26 seconds for the cup viscosimeter to sink when'the amount 90 of water in the'boil is 20 times the weight of the starch.- `When` considerably more de@ generatedstarchesam tested, only9 parts of water may be lused, or.9 to 1. v

- In the example o f-'glue above described, if slightly more water be used, as for, in

stance,411- parts instead of 3% parts, thejglue will be rendered more iuid and more'easily applied with a, brush and use'd for joint work. In such case, however, it -is desirable tofallow a-somewhat'longer ,time for more water. to dry out of the glueon thewood beforeyapplying the relatively-heavy pressure to theI glue jointw 'Example 2:/ G ood quality cassava starch is degenerated toa point such that it has-a viscosity of about 40 vat 9.to,1'when.treated v by the method abovev described. The def generation may be accomplished inany suit- 4able manner, as by the method described in 110 U. S. ll: atent1020656. i 100 pounds o f this -degenerated starch is mixed with 700 pounds of water and 4 poundsl of'caustic soda addedy inL a` solution thereof containing 60 pounds@V of water. The caustic soda solution is-added 1,15 slowly while the ftempe'rature ofthe batch vis raised to about 160 F. or somewhat less,

and with. continued agitation. When the batch has been transformed into glue vand become clear, V25 vpounds gum tragac'anth, `120 powderedto pass through a 60 mesh sieve,

is ladded and stirred in while the tempera- 1 ture of the batch lis maintained from F.

to F. for y1% hours. This gives a rela-'- tively Huid-l glue, easilymappliedby a snit- 1226-v -able brush, but owing apparently to 'the introduction-'of `the gum tiragacanth, the gl does not seem rto penetrate the wood'pore's so readily 'as would be-expected.

In applying this glue, and 'especially-to 130 veneers, it is, however, preferable to allow the surfaces to be glued to remain in contactfor about 3 hours without any substantial pressure being exerted on the joint, after which time a pressure of about 100 pounds per square inch or more may be applied until the glue'is practically dry and set.

Example .3: 100 pounds of raw cassava starch having a viscosity of about 100 at 20 to l, when tested-as above described, is sus` pended in 368 poundsof water and 8 pounds of caustic soda, dissolved in 32 `pounds of water, is gradually added with continued stirring, and the stirring preferably continued for about il; hour after the caustic solution has all been added. The resulting glue is less viscous or more fluid than the glue produced when the degeneratedstarch base o f Example 2 is dissolved in 2J2- times its welght of vwater with the 8%.of caustic soda.- Also the glue is not particularly prone to gelatinize on. standing if occasionally stirred, `and after being applied to veneers, and the Wood surfaces brought into juxtaposition, the veneers are preferably vallowed to stand for about 20 minutes with less than v20 pounds `per square inch' pressure applied thereto, after which a pressure .of 100 -pounds per square inch or more may be applied. The glue is more specially useful for heavy veneers and block Work or core stock..

Example 4:' 100 pounds of raw potato starch having a viscosity of '55 at 20 tol when testedby the method-above described, are suspended] in 280 pounds .of water, and .fl pounds of caustic soda-,dissolved in' 20 vpounds of water, are graduallyv added, with constant stirring, during a periodofabout l hour, during which'time the temperature of, the batch is raisedfrom 130 F. to a tem- 'perature from 150' F. to r1600v F. The resulting" glue is best applied warm` and the pipes through Iwhich -it is distribu ed -kept heated to a little above 140 until emptied. After the glueis 4applied to-'the wood, it' should be allowed to stand l() or 15 minutes without any substantial 'pressure being applied to the joint, afterwhich the Arelatively heavy final pressure may be applied inthe usual manner. However, if

the wood is hot, the time of standing should be increased to about 2L hour before the heavy pressure is applied. J

Example 5: 100 pounds of. raw cassavav starch having a viscosity of'about 8,0 at 20 to l whentestedby the above, describedv method, are mixed with 7 00 pounds of water,v vand 1 0 pounds Vof caustic soda, dissolved in 100 pounds of water,.ar'e slowly added withV constant stirring until the batchis transfA formed into. a homogeneous solution, and

` dered to pass through a mesh to the inch then 30 poundsof gum tragacanth, powfsieve, are vadded and thoroughly ,stirred 'in for -about'2 h ours.A The resulting glue is water absorbent material solutions when mixed wit used, as for instance viscose, or the xanthate in to a homogeneous Y glue solution.

thin enough to beapplied with a suitable brush, preferably a wire brush. After the glue is applied and the wood`faces placed in juxtaposition to one another, the joints are pounds of the degenerated starch base of Example 2 and 25 pounds of gum tragacanth, powdered to 60 mesh, are suspended in 350 pounds of water, and 4'pounds,of

caustic soda, dissolved in 30 pounds of water,

areslowly `added while the temperature of the batch is gradually raised to 150 F. to 160Q F. with continual rapid agitation. The

.rapid agitation is bestcontinued vuntil the glue is cold and -the glue maybe applied cold preferably to both faces to be joined. The gluedsurfaces should be allowed to -stand for about 3 hours without material preure being appliedxto the joints, after tically set. t l

. Instead of gum tragacanth, otherhighly rqducing viscous water, mayv be of cellulos'eor xanthate of starch may be used.

which 100 pounds per square inch may be applied to the joints until #the glue has prac-A Example 7 100 pounds of cassava starch of good quality having a viscosity-of about 90 at 20 to 1 when tested as above described,

is suspended in 468 pounds of water and 8,

pounds of caustic soda, dissolved in 32 pounds of water, together with 10 pounds-of carbon bisulfid, are slowlyadded during continued I rapid agitation; until the batch comes across The stirring is preferably not unnecessarily prolonged thereafter.' The starch is, I believe, put into the formfof xanthate of starch.

After the glue 'has been applied to the wood, it should be allowed t'stand for about hour without material pressure being applied to the joints', after which 100 pounds per square inch pressure may be applied,

Example .8: A solution of sodium aluminate is V-rst prepared by dissolving freshly precipitated 'aluminum hydroxidcontaining about 15% actual Al (Olii)3 ,washed nearly.

free from salts, inthe molecular quantity of caustic.- soda insolid forrn` (about 96% NaOH) to 'produce' sodium aluminate. -The solution" shouldycontain. 22.3% of sodium aluminateNa3AlO3. About 24h-.pounds of this .solution containing' about 5.5 .pounds of Napfll()3 `areadded to v375 pounds of waterand 10Q-pounds of the degenerated @cassava starch base of Example 2 are thenstirred'in and the`temperature raised to about160 F.

until the suspended starch and water are transformed into a homogeneous adhesive solution. Thel stirring is then continued y' until the batch is cold. If desired, the

taining the 3.5% of caustic soda and then perature, containing actually, or in effect, Na3AlO3. Sometimes it is desirable to add about 10% more of the l\Ta,AlO3 than above indicated. After the glue is applied tothe wood, it shouldl beallowed to stand for a substantial period without materially pressing the glue into the wood to allow a.' .sub-

stantial part of the water to dry outof the,

glue after which lthe final pressure mayl be applied to the joint to complete vtlie pressure of the glue into the wood.

vExample 9: Good quality ,cassava starch is degenerated to-apoint where its viscosity 4is about -60 at 9l -to 1, when tested bythe. vmethod. above described. The degenerationv may be carried out by any suitable method,-

such as by the degenerating agents specified in U.A S. Patent 1020656. 100 poundsof this 'pounds of water and 3 pounds lof caustic soda, dissolved in 32 pounds of water, grad.-

' uall'y -'added during `'twenty minutes', with lcontinual agitation, and while the'batch is kept at about 145 -F The resulting 'glue may be used `hot or cold, but after applica-'1 tion to the wood, the surfaces vto be glued areplaced adjacentone another yand slight-v4v l pressure applied, but insuiicient to cause theglue to be materially pressed into the wood? 1 0 pores. ,After about Ji hour, the pressure is increased to complete the pressure of the pressure 1s 1n all cases lequally good, if properly regulated, as will be apparent fromI the glue into the wood pores and the glue is perincreased pressure. v Example 10: Good qualityraw cassava mitted to further dry outand set underthis starch having a viscosity of 90 to 100 at'20 toll when tested as above described,'is mixed with twice its weight of Water,-.and while i "being agitated (based on dry weight of tliejstarch) of caustic fpotash iny 10%'solution in water is added- There is alsoadded about the same., time, from i% to 1% of sodium peroxid in 5% .solution in 'walten A- The mixtureis agitated for about v-12 hours -or more, until the starch has'been"degen erated to avpoint where its viscosityis from 24 '00.26 at 9to 1 when-tested as above del scribed. The ,percentages of reagents-added l may variedlsomewhatfto bring about the j deslred amount of degeneration. The starch glueb/Se isthlll further .treated with. i952?" sodium peroxid and t0rl;% potash,

` an Stinson as. beforaae waaien-being madeslowly. and with continual prevent the local bursting ofthe suspended the temperature raised to bring about 'solution, the liquid, upon `the raising of the tem-v .the final viscosity of the about -17- at 9 to 1.

by}Lette rsv Patent, is

starch particles, and the stirring'- co1'1tinued`- for several hours until the viscosity of the starch -isabout -26- at 9 to 1 when tested asf-above described. .Or the vstarch may 'be removed from the alkaline liquor and again suspended in 2 parts of water and of sodium peroxid and .of caustic pota'sh substantially like the lirst. vIn either case, starch is` reduced to The starch is finally removed .from' thel alkaline liquor and dried'and 100 poundsA` `and the starch given a second treatment i thereof suspended in 150 pounds lofwater and 16 pounds of caustic potash,'dissolved' vLin )E8-pounds of Water, added slowly with above. described, it may lbe `degenerated by any other-reagents@ method or a starch of the vproper viscosity selected, and then disl solved with the caustic potash as'above de# scribed. If heat nup to 150 F'. is used in the c lissolvin'g step, the percentage of caustic -potash used may beconsiderably reduced.

.The resulting glue is very permanent, and

in spite' of the small quantity of water there-'- degenerated starch base are mixed with-368- .30

in,.i s also very liuid and capable of ready ap' plication'by a suitable brush for joint work.v

Howeve'igafter being applied to the Wood,

it should be allowed to stand 15 or 20 minutes before very high pressure is applied. From the above, it will be seen that byiny invention', especially 1n vits broader aspects,

-many glues containing a relatively large v amount of water, -or being very iuid, or

both, are made commercially applicable and the disadvantages hereinbefore mentioned are substantially overcome.- I have found that a gradual fand at first low increase of above` examples, to anyone skilled in the art, after a'few trials, and, in somecases, this method hasV the advantageA Ofbringing all liol parts of the` glued surfaces earlier into contact without exerting excessive pressurey upon themass .of the glue. -Hence, I desire to cover all modifications and forms coming within' the language of the'appended claims. 'W'hat I claim as new and desireto secure 1. In the" improved process of'I gluingl '.Wood, the steps which consist in, applying to wood "ia water .containing glue made from a starchy carbohydrate base and al lowing the -glue to remainonl the wood for' fa' substantial' ,timev without material penetnatiforrA 'of the ,glue intol the'` wood and before" completing: the` ipressure; of thej glue *comp-165mg' .the v'pressure of the glue into int'o'the' fsupericialffvvoodpores to permiti' artlof'the water ign the gluethe superficial pores'of the wood and then pressing the glue farther into thewpores of the wood. I

2. In the., improved :process of gluing wood, the steps which consist in applying to the wood a glue containing a starchy carbohydrate base anid about four parts or more by weight of water and allowing -a substantial part ofthe water in the glue 0in the wood to dry out without material penetration of the vglue intoy the wood and before'pressing the glue materially into the superficial pores of the wood, and then applying pressure to the glue joint to force the glue farther into the superficial pores of the wood and' allowing the glue to further dry out under pressure.

3. In the improved process of gluing wood,` the stepsV which consist in applying to the wood ya glue containing" a starchyy ingthe glue to further dry out under pressure.

4. Inv the improved process of gluing together layers of wood, the steps which consist in applying to one or` both wood surf-aces to be joined a glue -containing a starchy carbohydrate base and Water, then placing the wood surfaces to be joined in juxtaposition -to one another and under a pressure of about l0 pounds per square' inbh or less for aperiod suicient to permit a substantial part of the water to dry out' 40v of the glue and without material penetration of the glue into the wood and then 'increasing the pressure/to about 100 pounds per square inch or more' and lallowing' the glue to further dry out under such increased pressure.

5. In the improved process of gluing' ltogether layers of woodl, the steps which consist in applying to one or both Wood surfaces to be joined a glue containing a starchy carbohydrate baseand water, then placing the wood surfaces to be joined in juxtaposition to one another and allowing' a substantial part vof the water intheglue on the Wood to dry out of the glue without.

material penetration of the glue into the wood vand before completing Vthe pressure of the glue into the wood pores and then applying pressurel to the glue joint to force the glue farther into the'pores of the wood land allowing the glue to further dry outy under pressure. l l 6. In the improved process of gluing wood, the steps which consist in applying to the wood a water containing glue an allowing ya substantial .part of the water y in the glue on the Wood to dry out of the glue without material penetration of the glue into the wood and before completing the pressure of the glue into the wood pores and then applyingpressure tothe glue joint. to force the glue farther into the pores of. .the wood and allowing the glue to. further dry out under pressure.

Signed at New York city, inthe county of New York and State of New York this 15th day of January A1 D. 1918.

' WILLIAM M', GROSVENQR. 

